The present invention broadly to a drive system for a self-propelled harvesting machine comprising a drive engine, such as an internal combustion engine, a transfer gearbox that is driven by the drive engine and which comprises a first driven pulley that is disposed on a drive shaft and drives at least one drive pulley of a working mechanism by a drive belt.
Document EP 1 875 933 A1 makes known a self-propelled harvesting machine designed as a forage harvester with a front attachment for picking up crop and an intake conveyor mechanism to feed crop that has been picked up by the front attachment to a chopper unit of the forage harvester. The chopper unit is disposed downstream of the intake conveyor mechanism and comprises a cutting cylinder that is driven by a drive shaft. The forage harvester has a drive system with a transfer gearbox, which has a driven pulley and is driven by an internal combustion engine. A drive belt designed as a main belt is wrapped around the driven pulley and, inter alia, drives the chopper unit and a hydraulic pump, which is used to drive the intake conveyor mechanism. The front attachment is driven by a primary transmission, which is assigned to the drive shaft of the cutting cylinder.
A disadvantage of the known drive system has proven to be that the drive of the hydraulic pump by the main belt, which requires a high drive speed, is carried out by a pump drive pulley having a small diameter. This results not only in the load caused by the drive of the hydraulic pump per se, but also in an additional load due to increased wear on the main belt.